Process for seamless-tube drawing



Apr. 3, i923. 1,450,699

A. c. MGRSE ET AL.

PROCESS FOR SEAMLESS TUBE DRAWING FiledSept. 15, 1921 Tube Drawing, ofwhich the following is a Patented Apr. 3, i923.

ALONZO CLAY HORSE AND HARRY RICHARD LEWIS, JR, OF SHELBY,

OHIG.

PROCESS FOR SEAIBiLESS-TUBE DRAWING.

Application filed September 13, 1:92 11. Serial No. 500,414. 3

To all wliom it may concern: I

Be it known that AIDNZO CLAY Morse and HARRY RICHARD LEWIS, Jr.,citizens of the United States of America, residing at Shelby, in thecounty of Richland and State of Ohio, have invented certain new anduseful Improvements in Processes for Seamlessspecification. 1

This invention relates to an improvement in the process of seamless tubedrawing, wherein through a definite step of heattreatment,the'qualit-ies and capabilities of the material for the. specificpurpose outlined, are materially increased.

In the ordinary method of tube making the billets are pierced white hotand rolled over plugs while hot, then pointed and pickled and colddrawnthrough a die over a mandrel. The product is then annealed in afurnace, at from thirteen hundred to fifteen hundred degrees F., andcooled. The pickling step is then repeated, and the material cold drawnover a. mandrel. The opera-- tions from the annealing step beingsucces-' sively repeated until the tubing has reached the desired size.

The improved step to'be introduced into the process outlined above, isthat of heattreatment of the material to a point just above the criticalpoint of the particular material being'used and in accordance with theproperties desired and quenching the heated material in a proper coolingmedium, This particular heatetreatment step results in a tempering-s'ocalledof the grain of the material, with the obvious advantage of a muchgreater tensile strength for the same ductility; a more uniform andbetter grain structure; presents a tubing capable of bet ter and moreperfect machining; and produces less scale in annealing, hence requiringless acid and time in pickling and cold drawlifter the tube is quenched,the temper is drawn by reheating to a temperature below that of thetemperature at which quenching is had, this drawing temperature, say ofa minimum of 300 F. being determined by the required characteristics ofthe final product, that is the'required degree of softness, ductility orother physical properties of the tubedesired. The tube is then allowedto cool and the ordinary operations of making its carbon desired size oftube is seamless drawn tubing repeated, until the obtained.

The use of this additional heat-treatment i step is not confined to anyparticular period of the complete process, as the usual proc- .css canbe followed to any desired size of cold drawn tube, the improvedheat-treatment step carr1ed out, and the original or other stepsemployed to complete the tube' formation.

Of course it is to be understood that the v The accompanying drawingillustrates a.

there-can be no specific inagnified section of material", that in Fig. li 5 showing the fiber construction of the material following the old andusual process; and

Fig-2 showing the same material following 1 the introduction of theheat-treatment step I of-the new process.

. The heat treatment, or grain refining step, may, of course, 'be usedin a particular operation as often as desired ornecessai'y; can beperformed at any time, after any heating precess of the material; or maybe carried outaft-er several steps or treatments of the tube. In otherwords there is no practical limitation to the application of the newstep.

Fig. 2 of the drawings, in comparison with Fig. 1, clearly indicates thefiber change in cident to the use of the new step, and the advantages ofthe resultant fiber arrangement will be obvious to one skilled intubedrawing processes.

The tube result-ant from the use of the new step is essentiallystronger, that is of greater tensile strength, than the tube resultantfrom the old or usual process. Therefore, the tube under the new processcan be made of much as was required in the old process. The possibilityof lower annealing heat prevents a large proportion of otherwise usualscale' accumulation, and also avoids the possibility of burning thefibers of the material. As a direct result of these conditions, thematerial can be worked at a much lower heat and much longer.

i nealin Having thus described the invention, What we cla m as new,1s:--

The close knitting of the fibers of the ma.- teriel resultant directlyfrom the new step of the process, permits a. much better ms.-

and capable of finer drawing, and one requiring less operations toperfect, and providing a better finished article, primarily incidenttothe permitted use of a lower/an- .temperuture.

1. A step in the process of seamless tube drawing, consisting in arefinement of the grain of the metal by heat-treatment. to upredetermined degree and then quenching.

- 2. A step in the process of seamless tube drawing, consisting inheating the'material to the upper critical point and quenchingintermediate the drewingsteps. I

3. A step in the process of seamless tube drawing, including heattreatment and ally refining the quenching prior to theannealing step.

4. A step in the process of seamless tube drswin consisting in annealinthe materinhrs eating to the upper critical point, quenching, and thentempering for additionu g grain of the metal over that oftlie'nnnealingtreatment.

5. A step in the process of seamless tuberirawing including heattreatment and quenching immediately following any independent heatingstep of the usual process.

6..Thatstep in a seamless-tube drawing process consistingin heating thematerial to s teupersture jfiist above the critical point end i on quencing.

before or between any of the drawing steps.

9. A step in a cold drawing tube process directed toward extremerefinement of the grain of the metel, consisting in heating the materialto the critical point and quenching in a cooling medium and thereafteranneal- %0. A- process for drawing seamless tubing consisting ofpiercing and drawing said billet over a. plugin a heated state, thenpointjust above the critical point, then quenching same in a coolingmedium; then re-heating to a temperature below the upper critical pointdepending on the character or quality of the steel desired and thenallowing same to cool and repeating the usual operations until the sizerequired is produced.

I 11. A process for drawing seamless tubing consisting of piercing abillet and drawing said billet over a plugin e hectedstet'e, then,

pointing-same, then heating same to a tempereture just above thecritical point, then quenching some in s cooling medium. then reheatingsame to a temperature between 300 F. and the upper critical point, deending on the character or quality of the tu e desired, and thenallowing same to cool and repeating the usual operation of drawing thetube until the tube is finished to the size desired.

In testimony whereof we aflix our signatures.

. ALONZO CLAY MORSE.

HARRY RICHARD LEWIS, JR.

mg same, then heatin same to a temperature

